Expanding the Public Sphere through Computer ... - ResearchGate

CHAPTER 6. ANALYZING THE TALK.ABORTION NEWSGROUP 80
Figure 6.3 on the following page illustrates the number of authors of each type
participating in the newsgroup by day. The entry, continuity and exit of authors to
the newsgroup can be summarized this way: on an average day in talk.abortion,
nearly 30 authors post messages who have written before, and will write again.
Additionally, about two authors join the conversation for the first time and make
a subsequent contribution at some later date; about three authors who had previously
contributed make their final contribution; and about four authors make
their one and only appearance in the conversation. Figure 6.4 on page 82 illustrates
the characteristics of threads using the same categories. On an average day
in talk.abortion, nearly 60 threads are continued from previous days and will be
continued on a subsequent day. In addition, about 11 new threads are started, to
be continued on subsequent days; twelve previously existing threads are ended;
and seventeen threads start and end. In short, talk.abortion is a dynamic conversational
environment, featuring an expanding and contracting base of authors and
threads, according to the needs and desires of its participants. It is clear that while
the talk.abortion newsgroup has a committed set of contributors, at the same time
a subset of constantly changing contributors is participating. To the extent that the
introduction of new participants is an indicator of diversity, talk.abortion can be
considered a diverse arena.
During the course of the study, nearly 3,000 different authors wrote at least one
message to the newsgroup. Most of these authors wrote very few articles. Eighty
percent of the authors wrote five or fewer articles, and more than 65 percent of the
authors wrote only once or twice to the newsgroup. Concentration ratios provide a
useful measure of participation. A graphic technique for summarizing concentration
data is a Lorenz curve, which shows as a continuous function the percentage
of total posts accounted for by an individual author, with the authors ranked in
order of post frequency. Two summary measures of concentration examined here
are the Gini coefficient and the entropy coefficient(Scherer 1980, Horowitz 1971).
The Gini coefficient measures the departure between the Lorenz curve actually
observed and the curve that would have appeared had all participants contributed
equally (Scherer 1980, 57). A Gini coefficient of zero indicates equality. Figure
6.5 on page 83 displays the Lorenz curve and shows the frequency of messages
posted by authors, illustrating the dramatic inequality of participation. One
half of one percent of the authors account for more than 40 percent of the articles
posted to the newsgroup during the study period; five percent of the authors
account for nearly 80 percent of the articles posted. The Gini coefficient for this
curve is calculated as .44, indicating a high level of concentration. The second